Study on the Influence of the Imidization Degree of Poly(styrene-co-octadecyl maleimide) as a Flow Improver in Waxy Crude Oils with Asphaltenes

Abstract

A series of poly­(styrene-co-octadecylmaleimide) with various imidization degrees as flow improvers for model waxy oils with asphaltenes were prepared through the reaction between octadecyl amine and poly­(styrene-co-maleic anhydride) (SMA) with random and alterative structure. With a small amount of the designed flow improvers, the wax crystals became fewer, smaller, and more dispersed in the oils, asphaltene particles were better dispersed, and the crystallization temperature and yield stress were reduced considerably. Moreover, it had been found that the performance of the resultant flow improvers for the bituminous paraffin oils is significantly affected by the imidization degree and maleic anhydride content, which are evaluated in terms of the polarity.

Preparation and Evaluation of Modified Ethylene–Vinyl Acetate Copolymer as Pour Point Depressant and Flow Improver for Jianghan Crude Oil

“…; and the third is the polymer including aromatic segments, such as poly­(maleic anhydride–benzyl alcohol), poly­(styrene–octadecyl maleimide), etc. Apparently, all of these PPDs contain nonpolar and polar moieties, which dramatically influence the efficiency of the PPD. ,, The nonpolar moieties can adsorb wax molecules and cocrystallize with them, whereas the polar moieties are responsible for providing electrostatic repulsion to wax crystals and disorganizing the crystallization process of wax. , Xu et al synthesized several poly­(maleic alkylamide−α-octadecene) copolymers with different contents of carboxyl group, and found that polar moieties could alter the shape of the wax crystal and prevent the wax from forming a layer structure. Erceg Kuzmić et al also revealed that the carboxyl group and heterocyclic nitrogen of the PPD could change the size of the wax crystal and reduce the gel strength of crude oil.…”

“…Apparently, all of these PPDs contain nonpolar and polar moieties, which dramatically influence the efficiency of the PPD. 6,17,18 The nonpolar moieties can adsorb wax molecules and cocrystallize with them, 19 whereas the polar moieties are responsible for providing electrostatic repulsion to wax crystals and disorganizing the crystallization process of wax. 20,21 Xu et al 22 synthesized several poly(maleic alkylamide−α-octadecene) copolymers with different contents of carboxyl group, and found that polar moieties could alter the shape of the wax crystal and prevent the wax from forming a layer structure.…”

Synthesis and Evaluation of Grafted EVAL as Pour Point Depressant for Waxy Crude Oil

“…Pour point depressant (PPD) which is comprised of polar moiety and nonpolar main chain, has been widely employed to improve the low-temperature flowability of crude oil. − The polar moiety can decrease wax crystal size and provide electrostatic repulsion force to wax crystals, whereas the nonpolar main chain is responsible for adsorbing and cocrystallizing with wax molecules. − In addition, it has been recognized that the introduction of alkyl side-chains can further enhance the effectiveness of PPD in reducing the pour point of crude oil. − Ren et al found that the short alkyl side-chains could largely improve the efficacy of poly­(maleic anhydride–methacrylate) by cocrystallizing with wax molecules. Xu et al revealed that the long alkyl side-chains of poly­(maleic alkylamide−α–octadecene) could stabilize crude oil by offering steric effects to wax crystals.…”

Enhancement of the Dispersion of Asphaltenes in Heavy Crude Oil by the Addition of Poly(Butylene Succinic Anhydride)‐based Dispersants

“…The asphaltenes found in the crude oil are the heaviest and nonvolatile substances. They are largely composed of condensed polyaromatic rings, containing aliphatic and naphthenic side chains and heteroatoms such as sulfur, oxygen, and nitrogen . Thus, the asphaltenes are the most polar fractions in the crude oil.…”

“…Thus, the asphaltenes are the most polar fractions in the crude oil. The asphaltenes also contain metals ( e.g ., V and Ni) as part of porphyrinic or nonporphyrinic groups . The numbers of the aromatic rings of the asphaltenes are in the range of one to seven in a single cluster, and the clusters are connected to each other by bridges, which leads to the formation of larger molecules .…”